1. Field of the Invention
The present invention relates to athletic shoes for conserving the energy of a Walker, a jogger, a jumper or a cyclist, and more particularly to a spring shoe device having pivoted hinged components for providing a spring action for storing and releasing energy, urging the wearer upward and forward during every movement cycle.
2. Description of the Prior Art
Many devices have been developed in the past for facilitating physical activity and, more specifically, walking, jogging, and the like. The primary object of these devices is for aiding a user, such as a jogger, to more easily bend and extend the legs thereby decreasing fatigue and enhancing the user's performance. Another important object of such invention is to dampen the impact on the legs of a user caused by the physical activity, such as jogging.
In most of these prior art devices, one end of a spring is attached to the bottom part of the user's leg, many times the foot, and the other end is attached to another part of the user's body, i.e., the waist or the thigh, using various attachment means. Depending upon the design of each device, the spring could be of either the tension or the compression type, a tension spring having a tendency to retract when stretched and a compression spring having a tendency to expand when compressed.
In operation, the spring acts as a shock absorber for the body upon impact with the ground as the hips, knees, and ankles bend for movement of the body. The spring is either stretched or compressed (depending upon its type) out of its original shape thereby absorbing some of the impact. As the back leg is extended to drive the body forward, as in a jogger's stride, the spring exerts a force, as it tends to return to its original shape, in parallel with the user's muscles, thereby aiding the user in the physical activity.
However, many problems are inherent in these energy-saving devices. For instance, those devices attaching to the user above the knee comprised springs or spring bars, are disposed away from the user's body, especially during the bending of the legs. Yagn, U.S. Pat. No. 420,179, shows an apparatus for facilitating walking, running, and jumping. The apparatus comprises a plurality of spring bars attached, at one end, to the user's feet by straps and, at the other end, to the waist and back of the user. As the user moves, for instance, in a jogger's motion, the bars alternatively bend and straighten in accordance with the user's stride thus facilitating the movement. The bars, however, bend away from the body thereby making the apparatus bulky and unable to be utilized beneath the user's clothing.
Anderson, U.S. Pat. No. 979,243, discloses a similar apparatus for facilitating walking comprising a plurality of spring bars attached at one end to the user's foot and to the user's thigh at the other end. As in Yagn, the spring bars bend and straighten in accordance with the user's movement, as in walking. Anderson has the similar problem as Yagn in that the bars bend away from the user's body thereby making it bulky and inconvenient to use. In addition, the Anderson apparatus shows the spring bar being strapped to the body above the user's knee, thereby making the apparatus uncomfortable and unattractive, especially if the user desires to wear short pants, short pants being normal attire for such physical activities.
Woodford, U.S. Pat. No. 4,294,338, discloses a lower limb aid device comprising an elastic strap behind the calf which is attached at one end to the "waist" of the user's foot and at the other end above the user's knee. The elastic strap is attached to the bottom of the user's foot using the well-known Velcro.RTM. brand hook-and-loop area fastener straps, wrapped forward of the user's heel, and attached above the user's knee again using Velcro.RTM. straps. In another embodiment, the elastic strap is comprised of two individual elastic straps which are attachable and length adjustable using Velcro.RTM. brand straps. The elasticity of the elastic strap provides an aid to the user's calf muscle in such activities as walking or jogging.
The Woodford device, however, does not provide absorptive propulsive forces in parallel with the natural movement of the user's foot, that is, in parallel with the pivoting motion of the user's foot about the ankle. In contrast, Woodford's elastic strap stretches and retracts in accordance with the movement of the foot, using the heel as a fulcrum. Therefore, the device described in Woodford does not aid the user's foot in pivoting at the ankle, but rather acts to pull the waist of the foot towards the heel of the user.
Furthermore, the Woodford device has problems in that it is inconvenient to use because the elastic strap must be attached to the user's foot and to the user's knee before putting on socks, shoes, pants, etc. In addition, it is unattractive to those users who want to wear short pants because the device is completely exposed from the user's ankle to the user's knee.